As NASA’s one-of-a-kind X-59 quiet supersonic research aircraft approaches first flight, its team is mapping every step from taxi and takeoff to cruising and landing – and their decision-making is guided by safety.
First flight will be a lower-altitude loop at about 240 mph to check system integration, kicking off a phase of flight testing focused on verifying the aircraft’s airworthiness and safety. During subsequent test flights, the X-59 will go higher and faster, eventually exceeding the speed of sound. The aircraft is designed to fly supersonic while generating a quiet thump rather than a loud sonic boom.
To help ensure that first flight – and every flight after that – will begin and end safely, engineers have layered protection into the aircraft.
The X-59’s Flight Test Instrumentation System (FTIS) serves as one of its primary record keepers, collecting and transmitting audio, video, data from onboard sensors, and avionics information – all of which NASA will track across the life of the aircraft.
“We record 60 different streams of data with over 20,000 parameters on board,” said Shedrick Bessent, NASA X-59 instrumentation engineer. “Before we even take off, it’s reassuring to know the system has already seen more than 200 days of work.”
Through ground tests and system evaluations, the system has already generated more than 8,000 files over 237 days of recording. That record provides a detailed history that helps engineers verify the aircraft’s readiness for flight.
“There’s just so much new technology on this aircraft, and if a system like FTIS can offer a bit of relief by showing us what’s working – with reliability and consistency – that reduces stress and uncertainty,” Bessent said. “I think that helps the project just as much as it helps our team.”
The aircraft also uses a digital fly-by-wire system that will keep the aircraft stable and limit unsafe maneuvers. First developed in the 1970s at NASA’s Armstrong Flight Research Center in Edwards, California, digital fly-by-wire replaced how aircraft were flown, moving away from traditional cables and pulleys to computerized flight controls and actuators.
On the X-59, the pilot’s inputs – such as movement of the stick or throttle – are translated into electronic signals and decoded by a computer. Those signals are then sent through fiber-optic wires to the aircraft’s surfaces, like its wings and tail.
Additionally, the aircraft uses multiple computers that back each other up and keep the system operating. If one fails, another takes over. The same goes for electrical and hydraulic systems, which also have independent backup systems to ensure the aircraft can fly safely.
Onboard batteries back up the X-59’s hydraulic and electrical systems, with thermal batteries driving the electric pump that powers hydraulics. Backing up the engine is an emergency restart system that uses hydrazine, a highly reactive liquid fuel. In the unlikely event of a loss of power, the hydrazine system would restart the engine in flight. The system would help restore power so the pilot could stabilize or recover the aircraft.
Behind each of these systems is a team of engineers, technicians, safety and quality assurance experts, and others. The team includes a crew chief responsible for maintenance on the aircraft and ensuring the aircraft is ready for flight.
“I try to always walk up and shake the crew chief’s hand,” said Nils Larson, NASA X-59 lead test pilot. “Because it’s not your airplane – it’s the crew chief’s airplane – and they’re trusting you with it. You’re just borrowing it for an hour or two, then bringing it back and handing it over.”
Larson, set to serve as pilot for first flight, may only be borrowing the aircraft from the X-59’s crew chiefs – Matt Arnold from X-59 contractor Lockheed Martin and Juan Salazar from NASA – but plenty of the aircraft’s safety systems were designed specifically to protect the pilot in flight.
The X-59’s life support system is designed to deliver oxygen through the pilot’s mask to compensate for the decreased atmospheric pressure at the aircraft’s cruising altitude of 55,000 feet – altitudes more than twice as high as that of a typical airliner. In order to withstand high-altitude flight, Larson will also wear a counter-pressure garment, or g-suit, similar to what fighter pilots wear.
In the unlikely event it’s needed, the X-59 also features an ejection seat and canopy adapted from a U.S. Air Force T-38 trainer, which comes equipped with essentials like a first aid kit, radio, and water. Due to the design, build, and test rigor put into the X-59, the ejection seat is a safety measure.
All these systems form a network of safety, adding confidence to the pilot and engineers as they approach to the next milestone – first flight.
“There’s a lot of trust that goes into flying something new,” Larson said. “You’re trusting the engineers, the maintainers, the designers – everyone who has touched the aircraft. And if I’m not comfortable, I’m not getting in. But if they trust the aircraft, and they trust me in it, then I’m all in.”
